Short Plated Column Reality Check

OK folks, there is a lot of "facts" circulating in various forums regarding the appropriate use of plated columns, so I am hoping that there is enough experience here with real life use to set some practical expectations.

1 to 4 plates. I have always held the belief that this set up is ideal for flavoured products. Grappa, Rum, etc. in fact I have one in the workshop partly built just for this purpose.

Now some folks even say that less than 6 plates is a waste of time. That is not my opinion.

5 plates and more. This is Vodka / Neutral territory.

But and it is a big BUT, this does not really factor in boiler charges or vapour speeds. It assumes that you are going for a fast production rate from fermented wash.

So for the folks that have tried the 2,3,4 & 5 plated options - what does real life say. Can you get close to neutral at low speed with 4 plates? Can you push out keg strength rum at a decent speed with 2 or 3 plates?

For me the 4 plate or less is a fancy pot still, but that is because I would use it as if it were a pot still. Other folks might use it in the same way as they would use a bigger plated column, for a neutral product.

So where do the boundaries lie? Are there any boundaries at all or can you produce azeotrope slowly on a short column if you really wanted to. Not sure WHY you would want to, but if you didn't have another option I suppose you might. I have tried the SPP filed column, and for me it does 1 job and 1 job only. I am expecting the short plated column to be far more versatile.

Have you tried to see what you can and can't do with the short column? Let us know.

Comments

The plated columns do have a range of performance based on heat thrown at the boiler and condensing knock down power.
I have no problem pulling 94 with the 4 plater.

IMO 5-8 plates put you into a sort of no mans land that is either too thin for whisky or not quite pure enough for that azeotropic neutral that the (packed) column guys are after. But at 5-8 plates I feel like the product is a very smooth white whisky. Perfect for this "moonshine" product being sold everywhere in stores nowadays.

I get (pro) guys that want to make vodka with 8 plates. But If they are trying to make money right out of the gate I try and get them to at least consider 10 even if they have their heart set on 8. They can always add on later. With 10 they can push a bit faster if needed.

I pretty much stick to 3-4 plates.

High Ridge Spirits and perhaps one or two others are using 2 plates for their whisky.

I have two pates and mostly make rum and UJSSM, but have had a go at WPOSW.
The rum comes off nicely but I am using it for aging and such so I get good flavours that mellow to really nice over 6 months or so. The UJSSM also does well off the two plates.
I have a 4" dephlagmator that will completely knock down the vapour but in ever get it to sit at a set proof/ABV it normally starts above 90% and then drops away to 65-60% and then after that it is all tails in the vast majority of cases. And yes it probably is just a fancy pot still in this mode.

For the WPOSW I think I am getting a nice clean flavour but I don't think it is azeotrope. It mixes well with the fruit washes and the panty droppers and does not have any of the sharpness that I used to get with the turbo washes (which I know makes sense)

I had a 50 l boiler that was getting 2200w thrown at it with no controller.

I disagree that a plated column with a dephlegmator being a fancy pot still.
Even one plate with a dephlem will give superior separation results vs a pot and extend the hearts cut.
I'm happy with 4 plates but happier with 6 plates. Although I can easily get azeotrope with 6 plates it is not a flavorless neutral and that's OK, too.

Browsing through the vodka section at the local hyper-mart I came across an expensive import (maybe from Sweden but not sure now) that bragged on the label that it was distilled 230 times (or it may have been 320 times). I assume that is the number of either physical or theoretical plates. My eyes glazed over as I tried to imagine a Dash300 :D

Lloyd don't get my intentions wrong. I am a big fan of a pot still and it was not meant as a criticism. What I was talking about was just the way it is run. The mode of operation.

For me a pot still mode on the column progresses like this. You initially stack the plates and then proceed with the run. Discard fores and heads as usual, and then take product. The ABV of the product gradually drops over the course of the run until you reach tails.

Whether you use 1 plate or 4 determines the starting ABV of the run. (Similar in principle to using thumpers on a pot still.) On a simple pot still the run might be considered to be: everything down to 75% is heads, Hearts is 75% to 65% (or 55%), after that is tails.

I have read good reports from someone running a 3" 4 plate column for whisky, that takes a hearts cut from 80% to 50% slow, at just 4 pints per hour.

In contrast the same column run in reflux mode could be producing white rum where the hearts cut remains stable at 93% for the entire run. Essentially being run in the same way as you would run a 10 plate column for Azeotrope - just taking your product at a different ABV.

I think the plated columns have the ability to be used in both ways, and that is something that it is difficult to do with any other option.

Thumper's have a few very specific uses that you can't replicate with a column, but for many pot-stillers the short plated column will make the pot still obsolete when it comes to the spirit run.

Oh my @Myles I didn't take it as criticism in any way. Just voicing my view and, as is typical, I could be wrong :)
You said:

Thumper's have a few very specific uses that you can't replicate with a column...

I've never run a thumper, please explain the reasons why it could be useful. I've heard of people pre-charging them with a flavorful liquid and the theory is that a thumper is a physical plate?
Starting to wonder if the gin basket could be modified to be a thumper and, if so, what would be the advantages.

I have a 4" 4 plate perforated setup now. last run (and I'm getting to know this rig better) I was able to pull the entire run of stripped product off at 92% with a very good rate of production. I didnt measure it but I pulled 5 liters of cuts off in about 4 hours from go till stop. it takes 45 minutes-1 hour to heat up.

to this rig I wanna add a 20" section with steel wool for more reflux to give a calculated 3.5 more plates. I think this should allow me to pull azeotrope at the same production rate. (thoughts or experience here?)

with the deplegmator I have and the water temp I put in (79F) I can only hold the vapor temp off the deplegm at ~160F at full flow, so my first bit comes over whether I want it to or not.

As I said I suspect my plated column will be used instead of my pot still for most of the flavoured products, except when I am doing a single run spirit. I am rebuilding my glycol pot still, but that was a special use tool anyway. I will probably still need a pot still option for strip runs.

Specific uses for a thumper:

Mostly for flavour modification where you are passing the vapour through a fruit pulp or a liquid. If you were using solids like crystal malt, then you could substitute a gin basket. In the traditional Caribbean rum process 2 thumpers are used and these are pre-charged with liquid. Heads in one and tails in the other.

The only other real application is protection of a worm condenser, where the thumper is used as device to pass clean vapour only. Anti puke device.

Although I did read of one distiller that was using a bottom plate with just an oversized downcommer and standpipes for the same purpose - no caps fitted. For puke protection of the plates.

Always excellent information @Myles.
It seems a thumper is usually much bigger than the GB4 gin basket, often about a 1/3 or even 1/2 of the size of the boiler.

@Fiji_Spirits my summertime cooling water temperature is just too high to knock back all the vapor in my 4" Dash so the super dephlem was developed for people like you and me. In the winter here the water is so cold the super is not needed and the regular size is probably easier to control. I've run the super a few times this winter and found it used so little (of the very cold cooling) water that the slightest change to the needle valve had a big effect.

Lately I've been playing with more input power and more reflux than what was my 'comfort' level. The results have been good up to a point but I seem to hit a wall at about 4kW with a 6 plate 4" setup and beyond that I don't seem to notice any reward for using more power or cooling water.
For quite some time I never ran more than about 3kW with the same setup and more often than not was using around 2400 to 2600 watts.
The package says 2000 watts for my elements but I've never tested them to know how accurate they are so this information could easily be off by an unknown percent.

In the conventional setup Lloyd your thumper sizes are correct, but many folks use smaller ones - but only because they include an overflow back to the boiler. The inline thumpers effectively do the same.

On the power issue did you find the column more "temperamental" at higher powers. Probably the wrong word - needing more supervision perhaps. I found with a packed column that it could very rapidly escalate to an Oh Shit! situation when pushing higher power levels.

Yes, @Myles the column was temperamental when pushed to higher (than my comfort zone) power level. It required some fiddling on my part to keep it in balance vs the 'set it and forget it' if using normal power - normal for me, that is.
I would encourage everyone to push your rig as hard as you can to learn it's maximum limits and back off from there to a point that you're comfortable with.
I'm now putting more power to the boiler than I used to but am not operating it at maximum.
A step or two below max is easier to operate and I enjoy not having to fiddle with the controls. And the new super dephlem has allowed me to throw a lot more power at the boiler than ever before, especially with this winters' icy cold water. With this seasons cold water the super is definitely overkill.

I keep thinking about the OP of this thread and keep coming back to believing that there are so many variables involved to form a simple conclusion. Number of plates, boiler power, reflux rate, boiler charge, composition of the ferment, etc...
But maybe the biggest variable is whether the environment is hobby or professional. A pro can probably afford the luxury of having a stripping still, a spirit still (whiskey) and a rectifying still (vodka) but the hobbyist would need to choose one all-purpose - and hopefully reconfigurable (modular) - still.

There are just so many choices now with easy to add new parts and more becoming available almost daily it seems.

I know what you mean Lloyd, I am looking at my still room and trying to figure out ways to rationalise it. I want to keep my glycol pot still but don't really need the second pot still. So they need to be combined, which means I can put the short plated column directly over the 100 litre keg.

That just leaves me the 3" VM column which either needs to go on its own boiler or to be added in somewhere.

:)):)) Well the keg whilst nice enough is a bit "ghetto" when you put it next to than nice new shiny one.
Jacketed? and what size is that. LOO drew me up some images, but since then I have changed them a bit and am taking mine up to 120 litres.

Yeah, jacketed and 70L. You are so right, the keg always looked good until this was put next to it. The keg served me well for a long time and it's almost like losing an old friend.
Some nice elements are in transit from @punkin and a pressure gauge is also on the way. Hoping to do a cleaning run soon.

I measured the space that she allots to me and ordered the biggest little boiler that would fit. It should work out well with the 50L fermenter.

I know this is drifting off topic, but it is my post!!! Just in case you intend to heat that beauty with fluid, and for anyone else that might be interested, here is something for you.

I am re designing my own glycol boiler at the moment, and increasing the size to 120 liters. However I am also going to put in an external glycol level control, as per the drawing below. It might be of interest as 1 way to do it, there are others off course, but this is relatively simple.

@Myles what keeps the glycol from taking the path of least resistance and just circulate in the heating/holding/pumping chamber? The 4 little overflow drops looks like the path the circulation would take. I must be missing something.

Unfortunately I won't be back in the workshop for another 2 months so it will need to wait.

Heating is applied inside the insulated boiler by an immersion element under the inner pot, the outer tank is just a reservoir/expansion chamber.

What you need to zoom in to see, is the small weir on the end of the inlet tube back into the reservoir. Just before the drops that overflow into the reservoir.

This isn't a circulating glycol system - it is just to maintain level control within the insulated boiler section. The outer reservoir is not heated.
You can circulate, but then you need high temperature pumps. This just uses a cheaper (and low flow) pump on a timer, just to trickle glycol to maintain the levels.

Heating the boiler fluid directly really does make perfect sense. Having an adequate space for the expansion of the hot fluid makes even better engineering sense. Having all that without the need for an extra overflow chamber will require a bit of thought. Thanks for the insight.

Is that pump physically located above the surface of the liquid in the reservoir? If so, you'll have issues, not many pumps will be able pull suction to refill (I understand this isn't a recirc … though perhaps it should be).

You have no way of getting air bubbles out of the top of the kettle - it would be easier if your overflow/expansion tank was taken from the top of the kettle, not the bottom. Picture how the coolant expansion tank/overflow works in your car. Under high temps some coolant is pushed out to the tank through a hose (which is constantly submerged) - when the coolant cools and contracts, it is pulled back out through the hose.

You could construct this system with absolutely no sizable external reservoir, only a small glycol overflow tank that could be continually topped off. In addition, at the top edge of the jacket you can add a fill port, which would also serve as a way to remove excess air.

Elements would be at the bottom of course, and rely on simple convection to carry heat upwards (I suspect this may lead to hot spots).

If that external reservoir is larger, why not insulate it, add the elements there, and plumb this baby as a recirc with a number of nozzles to ensure good coverage and heat transfer?

Unfortunately, when in use: you can't see the glycol, it has no level indicator, no drain etc. It works but is not user friendly.

It is fully insulated and works very well - it just needs improving. It is an aluminium pot, encapsulated in 2" thick expanded foam with a fibreglass outer skin. It will be a simple matter to cut the insulation and add a few extra connections.

Anyway - to get back on topic ;) who has tried adding a packed section on top of plates, and how much do you need to hit azeotrope, from 4 plates. I don't have the height so will have to make mine side mounted with a bottom drain back to the boiler.

Unless Lloyd convinces me to buy two 5" columns when they become available. :))

@Myles you devil, this discussion is best suited across several threads.

The internal heating was too well concealed on the post above, @grim's observations are noted and need to be addressed, but more importantly you bow out for 2 months after you place a very important brick on the "I'm doing this and what do you think" wall.

You are acting more and more like a retired American living in China and trying to explain why the next few months will be busy :)

Lloyd thanks for posting the picture of the table mounted column in the Loony Bin. I wish I produced enough vodka to justify the second column, but I just don't. For me it is a clean up to produce an occasional run of neutral for infused spirits and as a base for rum.

I will be using a 4 plated column most of the time, but table mounting a cut down version of my VM column to add on when it is required, is definitely something I wish to think about.

I am including plate disables so I can change the number of plates in use dependent on which product I am running at the time.
I think I am also going to put in a 5th plate at the bottom (just above the boiler) but as a puke preventer. Perhaps puke catcher is a better expression, no caps just downcommers and standpipes.